Jan Długosz University

About: Jan Długosz University is a education organization based out in Częstochowa, Poland. It is known for research contribution in the topics: Crystal structure & Luminescence. The organization has 749 authors who have published 2311 publications receiving 19395 citations. The organization is also known as: Higher Teacher Education School.

Influence of modifier oxide on dielectric dispersion and a.c. conduction phenomena of Li2O–Sb2O3–GeO2 glass system

Abstract: Li 2 O–Sb 2 O 3 –GeO 2 glasses mixed with different modifiers (viz., PbO, ZnO, BaO, SrO and CaO) were prepared. Electrical and dielectric spectral features have been studied over a wide frequency and temperature ranges. The real part of dielectric constant e′(ω), and loss, tan δ, have exhibited dispersion and relaxation effects with frequency and temperature. These results have been analyzed quantitatively on the basis of space charge and orientation polarization models. The a.c. conductivity in the low temperature region is explained based on quantum mechanical tunneling (QMT) model. The values of dielectric parameters were found to be the highest and the breakdown strength as well as the activation energy for conduction was found to be the lowest for PbO mixed glasses among all the studied glasses. The reasons for such variations in the values of these parameters due to the varying modifier oxides in the glass matrix have been discussed in the light of varying field strengths at germanium ion site (due to replacement of one modifier oxide with the other) with the aid of the data on Raman and IR spectral studies. Finally, it is concluded that CaO mixed glasses are more electrical resistant, whereas PbO mixed GeO 2 glasses are more conductive in nature.

Role of cation structure in the phytotoxicity of ionic liquids: growth inhibition and oxidative stress in spring barley and common radish

Abstract: The present study determines the influence of three ionic liquids (ILs) containing cations with diversified structure on the growth and development of spring barley seedlings and common radish leaves. Increasing amounts of 1-butyl-1-methylpyrrolidinium hexafluorophosphate [Pyrrol][PF6], 1-butyl-1-methylpiperidinium hexafluorophosphate [Piper][PF6], and 1-butyl-4-methylpyridinium hexafluorophosphate [Pyrid][PF6] were added to the soil on which both plants were cultivated. The results of this studies showed that the applied ILs were highly toxic for plants, demonstrated by the inhibition of length of plant shoots and roots, decrease of fresh mass, and increase of dry weight content. Common radish turned out to be the plant with higher resistance to the used ILs. The differences in the cation structure did not influence phytotoxity of ILs for spring barley. Furthermore, all ILs led to a decrease of photosynthetic pigments, which was directly followed by decreased primary production in plants. Oxidative stress in plants occurred due to the presence of ILs in the soil, which was demonstrated by the increase of malondialdehyde (MDA) content, changes in the H2O2 level, and antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). The changes in the chlorophyll contents and the increase of POD activity turned out to be the most significant oxidative stress biomarkers in spring barley and common radish. Both spring barley and radish exposed to ILs accumulated a large amount of fluoride ion.

Peculiarities of the environmental influence on the optical properties of push-pull nonlinear optical molecules: a theoretical study.

Abstract: Gas-phase geometry optimization of NLO-active molecules is one of the standard approaches in the first principle computational methodology, whereas the important role of the environment is usually not considered during the evaluation of structural parameters. With a wide variety of environmentally influenced models in most cases only the high quality single point calculations are prepared. Among different approaches, the most used polarizable continuum model (PCM) seems to be promising. In this study, we have compared the electronic properties of gas-phase optimized geometries of imidazole-derived push–pull compounds with those optimized using PCM solvation approach including CH2Cl2 and PMMA as media. We have focused particularly on the linear optical properties of investigated molecules, namely on the UV–vis absorption spectra. The analysis of presented results shows the applicability of the different quantum chemical (QC) methods for the UV–vis spectra calculations of linear NLO molecules. Herein we als...

Phase Transitions and Photoinduced Non-Linear Optics in TEA-CoCl2Br2 Nanocrystallites

Abstract: The photoinduced non-linear optics effects in the TEA-CoCl 2 Br 2 nanocrystallites incorporated into the photopolymer olygoetheracrylate matrices were investigated. The temperature dependence of the photoinduced second harmonic generation demonstrates a remarkable dependence on temperature near the phase transitions. It was shown substantial changes of the photoinduced nonlinear optics effects with decreasing of the nanocrystallite sizes confirmed by independent absorption measurements. Comparison with dielectric measurements was done.